In commonly owned U.S. Pat. No. 5,421,364 a flow-control valve is disclosed having a valve housing and a valve element in the housing rotatable about an axis through at most 360.degree. between a fully open position for substantially unimpeded fluid flow through the housing and a fully closed position for substantially no fluid flow through the housing and through intermediate positions for intermediate levels of flow through the housing. A spindle coupled to the element extends along and is jointly pivotal with the element about the axis. A handle or knob fixed on the spindle is provided offset from the axis with a handle stop so that the handle stop orbits about the axis as the handle and spindle are rotated to adjust the valve. An abutment body or sleeve fixed on the housing adjacent the knob carries a housing stop that is radially deflectable on the abutment body between a normal position angularly engageable with the handle stop for limiting angular movement of the handle and spindle and a deflected position out of angular engagement with the handle stop and permitting unimpeded angular movement of the handle.
Thus with this system the stop normally limits the angular stroke or travel of the valve spindle. This housing stop can, however, be depressed radially to let the handle stop pass, allowing the full range of adjustment to the handle.
While such a system is relatively effective, the radially depressible button is an extra part that increases construction costs. In addition manipulating such a valve requires a simultaneous radial pressure and rotation, just the type of unpopular biaxial actuation used for uncapping medicine containers to prevent casual opening and making even intentional use difficult.